Automatic resetting mechanism



E. T. PLATZ AUTOMATIC RESETTING MECHANISM May 1o, 1960 4 Sheets-Sheet 1Filed April 16, 1958 imlmwl Y lm. .MUINNI -N IUIHNI May 10, 1960 E. T.PLATZ AUTOMATIC RESETTING MECHANISM 4 lSheets-Shear. 2

Filed April 16, 1958 INVENTOR. fl [fl/00D T. /ZTZ 'Wdlnlnmmll May 10,1960 E. T. PLATZ AUTOMATIC- RESETTING MECHANISM Filed April 16, 1958 4Sheets-Sheet 3 INVENTO ,EU/V700 7.' PEZ/ifa May l0, 1960 E. T. PLATZ2,936,351

AUTOMATIC RESETTING MECHANISM Filed April 1e, 1958 @sheets-sheet 4 I Qlh H 47am/M United States Patent O l AUTOMATIC RESETTING MECHANISMElwood T. Platz, Detroit, Mich., assigner to r-'r-E Circuit BreakerCompany, Philadelphia, Pa., a corporation of Pennsylvania ApplicationApril 16, 1958, Serial No. 728,973

6 Claims. (Cl. 200-70) p My invention relates to a novel operatingmechanism for circuit breakers, and more specifically relates to atoggle operating mechanism for automatically resetting circuit breakersin which the frictional forces tending to oppose the automatic resettingmotion are reduced.

Toggle operating mechanisms for circuit breakers generally comprise apivotally mounted yoke which carries one end of an operating spring withthe other end of lthe operating spring operatively connected to 'theinovable contact. One such device is described in copending applicationSerial No. 426,223, tiled April 28, 1954, in the name of John A.yHerrmann et al. and assigned to the assignee of the instant invention. Y

When the movable contact of the above noted type mechanism is moved tothe open position by the operating spring, its motion is stopped by someexternally positioned stop means. connection is formed from thestopmeans through the contact arm to the 'operating spring and theportion of the yoke to which the operating spring is fastened?. Hence,the yoke will be forcedj into its pivotal mounting by the operatingspring to thereby cause an appreciable frictional force which opposes-rotation of the yoke about its pivot. f vIn an automatically Vresettingmechanism, the yoke Iis moved to its reset position primarily because ofthe in- 2,936,351 Patented May 1o, 1960 "ice 2 a novel toggle operatingmechanism for automatically resetting circuit breakers in which theforce Vof the toggle springs are isolated from the bearing of the toggleoperating link. A

These and other objects of my invention will become apparent from thefollowing description when taken in conjunction with the drawings inwhich- Figure 1 shows a top View of a multiphase circuit breakerequipped with my novel indicating structure with the top of the circuitbreaker removed. Y

Figure 2 shows a side view of the operating toggle mechanism for thecircuit breaker of Figure 1 when in the o position.

Figure 2a shows a side cross-sectional view of the operating yoke ofFigure 2.

Figure 2b shows a perspective view of the operatin yoke of Figure 2a..

Figure 3 is similar to Figure 1, and shows vthe multiphase circuitbreaker with its cover and operatingfhandle in place. Y Y

Figure 4 shows a side view of one phase of the circuit breaker of Figure1, and particularly illustrates the current path therethrough.

Figure 4a1 shows ra side cross-sectional View through one phase of thebreaker of Figure l when in the on position. Y

Therefore, a force transmitting Y ertia imparted to the yoke after aninitial collapse of This condition becomes more severe when the size of"the operatingA springs kare increased for circuit breakers havinglarger ratings, increased contact speed, or higher contact pressure.

" The essence of my invention is to substantiallyv elim- VFigure 5 showsan enlarged side cross-sectional view of the toggle mechanism of Figure2in the o or reset position. Y e

Figure 6 is similar to Figure S where the toggle mechanism is in the onposition. Y

Referring now to the figures, Figures l, 2, 201, 2b, 3, 4 and 4a setforth one type of circuit breaker Vto which my novel invention could beapplied. It is to be noted that while the following description of mynovel invention is made in conjunction with thespecifc circuit breakerof Figures 1 through 4, that any type circuit breaker which could be ofeither the single pole, or multi-pole type could be modified in-accordance with the invention.

As shown in Figures l and 3, the circuit breaker' `is of the three poletype having input line conductors 10, 12 and 14 for each respective poleand output load con ductors 16, 18 and 20 respectively for the samerespective poles. Each of line conductors 10,- 12 and 14 are takenthrough arc chute means 22, 24 and 2'6 respectively and are terminatedby a respective stationary contact such as contact 28 for the phaseincluding line member 14 as seen in Figures 4 and 4a, where Figures 4and 4a are Views of Figure 3 takenacross lines 4--4.

inate the above described frictional force at the yoke f* pi-vot byconfining the force of the operating spring wholly within the yoke afterthe initial contact opening operation. That is, in the past, one end ofthe operating spring was operatively connected to an external mem- 'berwhereby the other end drove the yoke into relatively vhigh pressureengagement. with its pivot bearing. I 'prevent this condition byproviding means within the yoke for engaging the end of the operatingspring which is operativelyl connected to the movable contact arm afterthe Contact opening operation so that both ends of the spring areconnected to the yoke and the spring is incapable of transmitting aforce to the yoke bearing.

Accordingly, a primary object of my invention is to provide a noveltoggle mechanism for circuit breakers.

Q ,Another object of my invention is yto decrease the' A still furtherobject of my invention is to provide Each of the stationary contactsthen cooperatefwith a respective movable contact such as movablecontacts 3 0, 32 and 34 (Figure 1). f f

As best seen in Figures l, 4 and 4a, each of fthe movable contacts areconnected to acommon operating bar 36 and are pivotally movable on bar36 to be movable into and out of engagement with their cooperatingstationary contact. The 'operating mechanismfor yoperating the movablecontacts will be set forth hereinafter in conjunction with Figures 2,2a, 5 and 6. u

As is best seen in Figure 4, each of movable contacts 30, 32 and 34 havea conductive pigtail such as pigtail 38 for stationary contact 34connected thereto which leads to a stationary conductor such asconductor 40, The conductor 40 for the phase including movable contact34 and the corresponding conductors of the other `two phases then have abimetal element associated therewith in thermal relationship, thebimetal for the phaseV shown in Figures 4 and 4a having bimetal element42. Clearly, the bimetal elements of each of the phases operate as theoverload trip elements for that phase.v

:3,936,351 Y -y l' Y f The conductors, such as conductor 40 thencontinue through a magnetic structure such as magnetic structure 44 inFigures 4 and 4a which has an armature member associated therewith. Thiscombination, as is well known in the art, and as described in copendingapplication Serial No. 706,169, iiled December 30, 1957, operates as theinstantaneous trip element for the circuit breaker, and operatesresponsive to short circuit currents in their respective phase.

As seen in Figure 1, each conductors 40, 46 and 48 for the highest,middle, and lowest phase or pole respectively emerge from theirrespective magnetic trip units and are connected to load conductors 16,18 and 20 respectively.

Accordingly, the current path for each pole is completed, and as bestseen in Figure 4 for the case of the highest pole in Figures 1 and 3, iscomprised of line conductor member 14, stationary contact 28, movablecontact 34, pigtail 38, conductor 40 and line conductor member 20.

'Ihe circuit breaker of Figures 1 through 4 is manually operated from arotary operating handle 50 seen in Figure l where, as shown by plaque52, the operating handle is rotated counter-clockwise to open thecontacts and clockwise to close the contacts.

As is more fully described in copending application Serial No. 706,186,tiled December 30, 1957, and assigned to the assignee of the instantinvention, the operating handle 50 is secured to operating shaft 54 ofFigures 1 and 4 which is seated in any desired manner in the casing ofthe circuit breaker. Shaft 54, as best seen in Figures 1, 2 and 4a hasan extending crank arm 56 rigidly secured thereto which has its outerend secured in a ball and socket connection to one end of member 58. The'other end of member 58 is secured in a `Second ball and socketconnection to a member (not shown) which is fastened to an operatingyoke 60.

Yoke 60 is pivotally supported about pivot point 62, as will bedescribed more fully hereinafter, and forms an operating toggle linkagewith link 64 (Figure 2) and springs 66 where one end of toggle link 64is positioned in a shoulder of latching cradle 68. The toggle linkage isthen connected to contact arm 33 through an intermediate link 70 whichis pivotally connected at the junction between spring 66 and toggle link64.

As best seen in Figures 1 and 3, each of the phases has an indicatingcylinder 74, 76 and 78 respectively associated therewith (Figure 1)which cooperate with windows `80, 82 and 84 respectively (Figure 3) incover 85 (Figure 4a) to present the appropriate contact indication to anobserver. More specifically, each of the phase indicators can presenteither an of't'j on, overload or short circuit indication through theirrespective Windows. Furthermore, they can present conditions particularto their own respective phase. By way of example, in Figure 3, thecircuit breaker has been tripped and a visual inspection clearly showsthat the breaker operated automatically because of an overload on thelower phase. Further details to the operation of this structure are setforth in copending application Serial No. 706,169, iiled December 30,1957.

The specific structure of my novel automatic resetting mechanism is seenin the oli position in Figure 5 and in the on position in Figure 6. Asheretofore described, the reset mechanism includes the toggle mechanismcomprised of members 60, 64 and 70 wherein the contact arms 33 (Figures2a and 2b) are on the output of the toggle drive system while springs 66actuate the system. As is best seen in Figures 2a and 2b, the operatingyoke 60 is journaled to the frame 90 to be pivotally mounted thereby.For example, projections 71 and 73 carried by yoke 60 may projectthrough cooperating openings in frame 90 schematically indicated inFigure 2b by dotted lines.

4 The latching mechanism for the above toggle system includes theintermediate latch member 89 which is pivotally mounted at pivot point92 and carries an extension of latching cradle 68 within slot 94. Theintermediate latch member -89 is latched by the auxiliary latch 96 whichis pivotally carried at pivot point 93. Aux-v iliary latch member `96 isin turn connected to latch member 100 which as is best seen in Figure 4acooperates with latching mechanism 109 which is operated from a commontrip system which is actuated by either thermal or mechanism tripelements as has been described in copending application Serial No.706,186, filed December 30, 1957, and assigned to the assignee of theinstant application.

Trip system 102 operates on a common tripper bar 104 which is rotatableto unlatch latch member' 100 and thus allow a clockwise rotation ofmember 100 about pivot point 98. This will cause the auxiliary latch 96to unlatch member 89 and thus allow cradle 68 to rotatecounter-clockwise about its pivotal support 106 in support 90.

When the circuit breaker is in its off and reset position, as seen inFigure 5, a rotation of operating handle 50 will cause yoke 60 to rotatecounter-clockwise about its journaled pivot 62 so that the top of spring66 supported by yoke 60 passes across the line defined by point ofengagement of link 64 and cradle 68 and the lower end of spring 66 andits attachment to link 70. This will cause the lower end of link 64 tosnap to the left to thereby drive link 70 downwardly so that contactarms 33 attached at pivot 108 of link 70 are moved toward the engagedposition of Figure 4a.

If, while the breaker is in the on position of Figure 5, the trip unitis operated to unlatch latch 96, the auxiliary latch member 89 willrotate counter-clockwise under the force of cradle 68 which is biasedcounterclockwise by the toggle springs 66 operating through llink 64.The counter-clockwise motion of cradle 68 will bring the upper point oflink 64 to the left and to a position where the toggle formed by links64 and 70 breaks to the right. With the toggle defeated, the force ofopening springs 66 are exerted on contact arms 33 to move the contactarms upwardly and towards a disengaged position.

At the same time, the reactive force of contact arms 33 will operate onyoke 60 so as to initiate the rotation of yoke 60 in a counter-clockwisedirection and thus initiate the resetting operation while the contactsare still moving their disengaged position. That is to say, while spring66 contracts to draw contact arms 33 upwardly, there is an equal andopposite force exerted on the yoke at the point at which the spring 66engages yoke 60. The component of this force is perpendicular to theline joining the pivot 62 of yoke 60 and is directed to the right, andit is this component of force which causes the motion of yoke 60 towardsits reset position.

It is now to be noticed that if the contact arms 33 are moved to a fullyopen position against some external stop member, that the forcetransmitted through springs 66 to the stop member would include thejournal bearing 62. This may be seen in Figures 2a and 2b where therewould be a connection from the top of the yoke 60 through springs 66,link 70, contact arms 33, and to the external stop. This spring forcewould operate to drive yoke 60 into its journaled bearing 62 to therebycreate a relatively high frictional force which would oppose the freerotation of yoke 60.

In accordance with the instant invention, the yoke 60 has inwardlyprotruding semi-cylindrical projections 112 and 114 which may beintegral with the bearings of the yoke and extending over the outwardlyprotruding ends ofpivot shift 108.

Accordingly, as the contact arms 33 are drawn upward- 1y during contactdisengagement, the protruding ends of shaftl will seat insemi-cylindrical projections 112 'and 114 prior to the engagementofcontact arms 33 with any external stop member. Therefore, the motionof contact arms 33 is limited by the distance that shaft 108 maydriveprior to engagement with projections 112 and 114. Once the shaft 108seats within projections 112 and 114,-the force of operation springs 66is completely confined within the operating yoke 60 and no additionalforce will now be transmitted to the journal bearings 62. By soconfining the operating force of springs 66, these springs may be aspowerful as required and still will not transmitany vforce opening todrive yoke 60 into journal bearings 62. y

Since the force of springs 66 is confined, the initial rotation impartedto yoke 60 will now. be suicient to allow yoke 60 to continue itsclockwise rotation after the contacts'have been disengaged. Therefore,links 64 and 70 will be moved from the position of Figure 6 and towardthe position ofr Figure 5 and cradle 68 and its associated intermediatelatch 89 will be permitted `to return to a latching position. For thispurpose, alight auxiliary spring (not shown) may be associated withlatch cradle 68. Hence, the breaker will be automatically reset afterits automatic operation due to automatic tripping through trip unit 102.

Similarly, a relatively light handle return spring may be wound on thelower end of the operating handle shaft to supply energy for bringingthe operating yoke to its off position in the event that duringautomatic tripping, the operating handle is held in its on position byan operator.

In the foregoing, I have described my invention only in connection withpreferred embodiments thereof. Many variations and modifications of theprinciples of my invention within the scope of the description hereinare obvious. Accordingly, I prefer to be bound not by the specificdisclosure herein but only by the appended claims.

I claim:

l. An automatic resetting mechanism for a circuit breaker; saidautomatic resetting mechanism comprising a yoke member operativelyconnected to the operating handle of said circuit :breaker andsupporting a first end of an operating spring, a toggle mechanism havinga first portion thereof connected to a second end of said operatingspring and a second portion thereof operatively connected to thecooperating contacts of said circuit breaker; said operating springbeing loaded responsive to operation of said yoke member to a closedposition to move said contacts to an engaged position through saidtoggle mechanism, said spring moving said contacts to a disengagedVposition responsive to breaking of said toggle mechanism; and confiningmeans operatively connectable to said second end of said spring todirectly connectV said second end of said spring through ia rigid member.to said first end of said spring when said cooperating contacts aredisengaged.

2. An automatic resetting mechanism for a circuit breaker; saidautomatic resetting mechanism comprising a yoke member operativelyconnected to the operating handle of said circuit breaker and supportinga first end of an operating spring, a toggle mechanism having a firstportion thereof connected to a second end of said operating spring and asecond portion thereof operatively connected to the cooperating contactsof said circuit breaker; said operating spring being loaded responsiveto operation of said yoke member to a closed position to move saidcontacts to an engaged position through said toggle mechanism, saidspring moving said contacts to a disengaged position responsive tobreaking of said toggle mechanism; and confining means operativelyconnectable to said second end of said spring to connect said second endof said spring through a'rigid member to said first end of said springwhen said cooperating contacts are 6 disengaged;said confining meansbeing rigidly supported by said yoke member, said operating'spring beingcompletely confined within said yoke member after said cooperatingcontacts are disengaged. A

3. An automatic resetting mechanism for la circuit breaker; saidautomatic resetting mechanism comprising a yoke member operativelyconnected to the operating handle of said circuit breaker and supportinga first end of an operating spring, a toggle mechanism having a firstportion thereof connected to a second end of said operating spring and asecond portion thereof operatively connected to the cooperating contactsof said circuit breaker; said operating spring being loaded responsiveto operation of said yoke member to a closed position to move saidcontacts to an engaged position through said toggle mechanism, saidspring moving said contacts to a disengaged position responsive tobreaking of said toggle mechanism; and conning means operativelyVconnectable to said second end of said spring to connect said secondend of said spring through a rigid member to saidv first end of saidspring when said cooperating contacts are disengaged; said confiningmeans being rigidly supported by said yoke member, said operating springbeing completely confined within said yoke member after said cooperatingcontacts are disengaged; said yoke being thereafter free to moveindependently of the force of said spring.

4. An automatic resetting mechanism for a circuit breaker; saidautomatic resetting mechanism including a pivotally mounted yoke member,an operating spring, a toggle mechanism and a latch means; saidpivot-ally mounted yoke member having one end of said operating springattached thereto, said toggle mechanism forming an operative connectionbetween the other end of said operating spring and a movable contact ofsaid circuit breaker, said latch means being operative to latch saidtoggle mechanism in a latched position, said yoke member operatingthrough said operating spring being operative to drive said movablecontact to an engaged position and load said operating spring when saidtoggle mechanism is latched and said yoke member is moved to a closedposition; said latch member being defeatable responsive to predeterminedconditions toV allow said toggle to break, said movable contact beingmoved to a disengaged position by said operating spring when said togglebreaks; and

V confining means operatively connectable to said end of said springconnected to said toggle mechanism when said movable contact moves tosaid disengaged position to rigidly connect each of said ends of saidoperating spring and preventing the force of said operating spring frombeing applied to the pivot point of said pivotally mounted yoke member.

5. An automatic resetting mechanism for a circuit breaker; saidautomatic resetting mechanism including a pivotally mounted yoke member,an operating spring, a toggle mechanism and a latch means; saidpivotally mounted yoke member having one end of said operating springattached thereto, said toggle mechanism forming an operative connectionbetween the other end of said operating spring and a movable contact ofsaid circuit breaker, said latch means being operative to latch saidtoggle mechanism in a latched position, said yoke member operatingthrough said operating spring being operative to drive said movablecontact to an engaged position and load said operating spring when saidtoggle mechanism is latched and said yoke member is moved to a closedposition; said latch member being defeatable responsive to predeterminedconditions to allow said toggle to break, said movable contact beingmoved to a disengaged position by said operating spring when said togglebreaks; and confining means operatively connectable to said end of saidspring connected to said toggle mechanism when said movable contactmoves to said disengaged position to rigidly connect each of said endsof said operating spring and preventing the force of said operating vspring attached thereto, said toggle mechanism forming an operativeconnection between the other end .of said operating spring and a movablecontact of said circuit breaker, said latch means being operative tolatch said toggle mechanism in a latched position, said yoke memberoperating through said 'operating spring being operative to drive saidmovable contact to an engaged position and load said operating springwhen said toggle mechanism is latched and said yoke member is moved to aclosed position; said latch member being defeatable responsive topredetermined conditions to allow said toggle to break, said movablecontact being moved to a disengaged position by said operating springwhen said toggle breaks; and coniining means operatively connectable tosaid 4encl of. said spring connected to Vsaid toggle mechanism when saidmovable contact'moves to said disengaged position to rigidly connecteach of ,said ends-of said operating spring and preventing the force ofsaid operating spring from being applied to the pivot point ,of saidpivotally mounted yoke member; said coniining means being supportedwithin said yoke member; said operating yoke being relatively free torotate to an open and reset position after unlatching of said latchingmeans independently of friction at said pivot point normally caused bysaid operating spring.

References Cited in the tile of this patent `UNITED STATES PATENTS1,786,798 Von Hoorn Dec. 30, 1930 1,815,561 Getchell July 21, 19311,952,039 Frank Mar. 20, 1934 1,985,023 Dorfman Dec. 18, 1934 2,357,210Leonard Aug. 29, 1944 2,829,219 Christensen Apr. 1, 1958 2,830,154Herrmann et al Apr. 8, 1958

